Robustness Analysis of African Genetic Ancestry in Admixture Regression Models of Cognitive Test Scores

Abstract

Admixture regression involves the regression of a medical or behavioral trait on sub-population admixture proportions, race and ethnic group identifiers, and other explanatory variables, to measure the environmental and genetic components to trait variation across self-identified racial and ethnic groups. Several recent admixture regression studies find that proportion of African genetic ancestry has strong explanatory power for cognitive ability test scores. This paper applies stratified sub-sampling to explore the possibility that potential model mis-specification and/or variable mis-measurement underlies this empirical finding. The estimated coefficient on African ancestry is not significantly changed when the sample is stratified by low socioeconomic status/high socioeconomic status, Hispanic/non-Hispanic, Black-only/Black-White biracial, or Black/White racial group self-identification. Keywords: Robusticity tests, Admixture regression, Cognitive ability